[c-nsp] BGP <-> OSPF default route failover

[Pete S.]

I'd imagine you aren't completely redistributing your bgp tables into
OSFP, and from your diagram I'll assume you are doing ibgp between
your edge routers already.  So build a prefix list, and route-map,
which permits only the default route from bgp.  Redistribute the bgp
process into ospf, based on that route-map, as an E1 type.  This will
put the default into your ospf area, and traffic will flow towards the
closest exit.  If you rather a primary/secondary, use the ospf E2 type
and assign a large metric to your secondary.

I haven't checked the syntax, but this should probably point you in
the right direction.

!On your BGP routers
!
ip prefix-list bgp_default->ospf seq 5 permit 0.0.0.0/0
ip prefix-list bgp_default->ospf seq 100 deny 0.0.0.0/0 ge 1 le 24
!
route-map bgp->ospf permit 10
 match ip address prefix-list bgp_default->ospf
!
router ospf 100
 ! I assign an arbitrary site ID, and then prepend my AS onto it but
whatever suits you, tag is optional
 ! select your own metric-type and metric depending on the exit
behavior you want.
 redistribute bgp 65535 metric-type 2 metric 100  tag 6553501
route-map bgp->ospf
!
!



--Pete